The present invention relates to a substrate transport method, a substrate transport apparatus, an exposure apparatus, and a device manufacturing method. More particularly, the present invention relates to a substrate transport method and substrate transport apparatus suitable for loading a wafer serving as a substrate onto a wafer stage of an exposure apparatus, or unloading a wafer from a wafer stage, and to an exposure apparatus using this, and to a device manufacturing method using the exposure apparatus. This application is a continuation application based on PCT/JP98/05453.
FIG. 62 and FIG. 63 are diagrams for explaining the construction of a conventional substrate transport apparatus. FIG. 62 is a plan view, and FIG. 63 is an elevation view of an arm section. The substrate transport apparatus comprises a load arm 412 and an unload arm 413, and they are able to move back and forth along a longitudinal direction of an arm guide 414 while being guided thereby so as not to interfere with each other. Furthermore, each arm 412 and 413 respectively incorporates a pair of substrate support portions 412a and 413a. On the tip ends of these are formed wafer attraction portions 412b and 413b. 
An unprocessed wafer W which has been transported to the position shown in the figure by the load arm 412, is transferred to pins of an XY stage side (not shown in the figure), on release of attraction by the wafer attraction portions 412b. The load arm 412 which has completed transfer is then retracted and moved to bring in another wafer W. The wafer W which has been transferred to the pins is attracted and held on a mounting table of the XY stage with the lowering of the pins, and is moved to another location together with the XY stage, to be subjected to predetermined processing such as exposure.
The unload arm 413 is moved to the standby position shown in the figure, either during processing of the wafer W or immediately after processing. When the wafer W for which processing has been completed comes to the position shown in the figure together with the XY stage, the pins and the wafer W are raised. Then, at the stage where the wafer W has been raised to a higher position than the substrate support portion 413a, the unload arm 413 is moved to the transfer position shown by the load arm 412 in the figure, and the wafer W is received.
However, in the substrate transport apparatus as described above, the standby position of the unload arm 413 must be such that the arm is separated more than a distance xe2x80x9cdxe2x80x9d from the wafer W so that the wafer attraction portions 413b and the wafer W do not interfere. Moreover, for example when the wafer W is received by the unload arm 413, it is necessary to move the unload arm 413 from a standby position A as far as a transfer position B. Therefore there is a problem of a drop in throughput of wafer W transport or processing, attributable to the time requirement for movement during this interval.
[Second Background Art]
Furthermore, at the time of manufacturing semiconductor devices or the like, for the exposure apparatus for transferring a pattern of a reticle serving as a mask onto each shot region of a wafer (or glass plate etc.) to which photoresist has been applied, conventionally a projection exposure apparatus of the step-and-scan type (block exposure type, or stepper type) is widely used. On the other hand, recently, in order to respond to the demand for precise transfer of large area circuit patterns, without making the burden on the projection optical system too heavy, attention is also being given to projection exposure apparatus of the scanning exposure type such as the so called step-and-scan type. According to such apparatus, step movement is carried out between shots, and at the time of performing exposure to each shot region, the reticle and the wafer are moved simultaneously with respect to the projection optical system.
With these projection exposure apparatus, in order to increase throughput, a wafer loading operation for unloading a wafer which has already been exposed on a wafer stage used for positioning and moving the wafer, and also loading an unexposed wafer onto the wafer stage, must be carried out at high speed.
A conventional wafer loader system comprises; wafer lift pins projectably provided in a wafer holder of the wafer stage, a wafer load arm for mounting the wafer on the wafer lift pins, and a wafer unload arm for removing the wafer from the wafer lift pins. Furthermore, as disclosed for example in Japanese Patent Application, First Publication, No. 9-36202, when the wafer is mounted on the wafer stage, rough alignment (prealignment) based on the external shape of the wafer is performed beforehand at the stage where the wafer is transferred from the wafer transport line to the wafer load arm.
Moreover, in order to perform wafer exchange, the wafer stage is moved to a loading position, and attraction of the exposed wafer on the wafer holder is switched off. After this, the wafer is raised together with the wafer lift pins, and then the wafer unload arm is inserted between the wafer and the wafer holder, and the wafer lift pins lowered so that the wafer is transferred to the wafer unload arm.
After this, the wafer unload arm is taken out from the loading position to the wafer transport line side, and at the same time, a wafer load arm holding an unexposed wafer is inserted into the loading position, and the wafer lift pins are raised so that the wafer is transferred onto the wafer lift pins. Then, after the wafer load arm is withdrawn, the wafer lift pins are lowered so that the wafer is mounted on the wafer holder. After this, attraction by the wafer holder is switched on. The wafer stage is then sequentially moved to positions where search alignment marks on the wafer are within detection regions of an alignment sensor, and search alignment is performed.
Moreover, in the search alignment process, for example, by detecting the position of three one dimensional search alignment marks on the wafer, the positional displacement amount and the rotation angle deviation amount of the origin of the shot array on the wafer is detected, and based on these results, the actual rough array coordinates for each shot region on the wafer are obtained. After this, the final alignment (fine alignment) is executed for example by an EGA (Enhanced Global Alignment) method. This involves detecting based on the rough array coordinates, the position of fine alignment marks (wafer marks) attached to a predetermined number of shot regions (sample shots) determined beforehand on the wafer by an alignment sensor. Then based on this result, the pattern images of the reticle in each shot region of the wafer are precisely overlapped and exposed, after which the abovementioned wafer exchange is again performed.
In the conventional technology as described above, the wafer lift pins are protrudably mounted in the wafer holder on the wafer stage, and by raising these wafer lift pins, transfer of the wafer is performed between the wafer holder and the wafer load arm or the wafer unload arm.
However, in the construction where the wafer lift pins are provided inside the wafer holder, the mechanism for the wafer stage for supporting the wafer holder becomes complicated, and there is the disadvantage of the increase in size. In particular, in order to increase throughput, it is necessary to increase stepping speed in a one-shot exposure type, or stepping traversing speed and scanning speed in a scanning exposure type. However, in the case of enlargement of the drive motor, there is the possibility of an increase in vibration and generated heat. Therefore, in situations where the wafer stage cannot be made small, it is difficult to raise the traversing speed while suppressing heat output and the like.
Furthermore, the conventional processing time for one wafer is determined from the sum of; the wafer exchange time, the search alignment time, the fine alignment time, and the time for actually transferring the pattern image of the reticle to each shot region (strict exposure time). Therefore, even if the wafer exchange time or the wafer alignment time are shortened, the throughput for the exposure step can be increased. Therefore, it is desirable to shorten as much as possible the wafer exchange time or the wafer alignment time.
Furthermore, heretofore after performing prealignment of the wafer at a position away from the projection exposure apparatus, the wafer is transferred onto the wafer stage by the wafer load arm. Therefore, due for example to the positioning accuracy of the wafer load arm, there is the possibility of a drop in the prealignment accuracy. Therefore, heretofore after attracting and holding the wafer on the wafer holder, and before executing fine alignment, it is necessary to execute a search alignment to roughly measure the shot array on the wafer. Thus the time required for alignment is increased. In order to eliminate such search alignment, it is necessary to increase the positioning accuracy of the wafer at the stage where the wafer is mounted on the wafer holder.
Furthermore, in the case where for example during the time until the wafer is mounted on the wafer holder, the position of the external shape of the wafer is detected, when the reflected light from the wafer is received by an epiflourescent illumination method, then due for example to the condition of the material of the coating on the wafer surface, or the inclination (differences in level) of the surface, the condition of the reflected light can change relatively largely. Therefore, there is the possibility of a drop in position detection accuracy.
[Third Background Art]
FIG. 64 shows an example of a wafer transport system for this type of apparatus. Using FIG. 64 to briefly describe the processing flow of the wafer transport, a wafer W which has been fed from another semiconductor manufacturing apparatus on the line such as a coater-developer (an apparatus for applying photoresist to the wafer, and then developing the wafer after exposure), is transferred to a robot arm 464, and is attracted by an attraction portion 468 on the robot arm 464 and held. After this, the robot arm 464 is driven along a guide 467 in the direction of arrow A by an arm drive unit 466, and the wafer W is carried by the robot arm 464 to infront of a prealignment apparatus 470. At this position, the robot arm 464 is extended so that the wafer W is transferred onto a rotation shaft 472 on the prealignment apparatus 470.
A control unit 474 rotationally drives the rotation shaft 472 via a drive mechanism (not shown in the figure) constituting the prealignment apparatus 470. As a result, the wafer W starts to rotate. During this rotation of the wafer W, the control unit 474 monitors the output from a notch detector (not shown in the figure) and waits until a notch (V shape notch) provided on a peripheral portion of the wafer W is detected. When the notch is detected by the notch detection sensor, the control unit 474 stops the rotation of the rotation shaft 472 via the drive mechanism. Then, the control unit 474 simultaneously drives positioning pins 476, 478, 480 via a pin drive mechanism (not shown in the figure) towards the rotation shaft 472. As a result, rough positioning (prealignment) of the wafer W in the rotation direction and the XY two dimension direction is completed. After completion of this prealignment, the control unit 474 return the positioning pins 476, 478, 480 to their original positions.
Next the control unit 474 drives an arm drive mechanism 484 constituting a rotary transport arm drive apparatus 482, so that a wafer loader rotary transport arm 486 is turned to a position where a clasp portion on the tip end of the rotary transport arm 486 is engaged with the rotation shaft 472 on the prealignment apparatus 470, and stops there. After this, the vacuum is switched on for the attraction portion 488 provided on the rotary transport arm 486. As a result, the wafer W is attracted and held on the rotary transport arm 486. In this condition the rotary transport arm 486 stands by. During this standby, exposure of a wafer W mounted on an XY stage 490 is completed, and exchange of the wafer W is performed according to the following (1) through (10) procedures in approximately 5 to 10 seconds.
(1) The XY stage 490 is moved by a main control unit (not shown in the figure) via a drive system to the loading position.
(2) Next, the vacuum of a wafer holder 492 is switched off by the main control unit.
(3) Then, three lift pins (center-up) 494, 496, 498 provided on the XY stage 490 are raised by the main control unit so that the wafer W is lifted up by the center-up pins 494, 496, 498 and separated from the wafer holder 492.
(4) Next, the arm drive mechanism 484 is controlled by the control unit 474 in accordance with instructions from the main control unit, so that a wafer unload rotary transport arm 500 is inserted beneath the wafer which is being held by the center-up pins 494, 496, 498.
(5) Then, the center-up pins 494, 496, 498 are lowered by the main control unit so that the wafer W is transferred to the rotary transport arm 500. At this time, the vacuum for the wafer W by means of the attraction portion 502 of the rotary transport arm 500 is started by the control unit 474.
(6) Next the rotary transport arm 500 is turned by the control unit 474 so that the wafer W is withdrawn from the loading station, and at the same time the rotary transport arm 486 which is standing by while holding the wafer W is turned so that the wafer W is transported to above the wafer holder 492.
(7) Then, the center-up pins 494, 496, 498 are raised by the main control unit so that the wafer W is transferred from the rotary transport arm 486 to the center-up pins 494, 496, 498.
(8) Next, the rotary transport arm 486 is withdrawn from beneath the wafer W by the control unit 474.
(9) Then, the center-up pins 494, 496, 498 are lowered by the main control unit so that the wafer W is mounted on the wafer holder 492.
(10) After this, the vacuum of the wafer holder 492 is switched on by the main control unit.
With the recent progress of high integration of devices, a limit is starting to be seen in the use of light in exposure methods. For example, in the case where exposure is performed with a device rule (minimum line width) of less than 0.18 xcexcm line and space (L/S), it has become necessary to use a projection optical system having a high N.A. (0.6xcx9c0.75) using a short exposure wavelength of for example, an excimer laser (KrF: wave length 248 nm, ArF: wavelength 193 nm) or an F2 laser (wavelength 157 nm). The reticle size also has shifted from 6 inches to 9 inches. Under such circumstances, there has also been an increase in demand for exposure apparatus which can obtain a high throughput, and for example, in the case of a scanning type exposure apparatus of the scanning stepper type, in order to shorten the exposure time, it has become desirable to have a higher acceleration and speed for the reticle stage on which the reticle is mounted, and the wafer stage (XY stage) on which the wafer is mounted.
However, if the reticle stage and the wafer stage are further accelerated, the synchronization adjustment of the two stages becomes difficult, so that the adjustment time is increased. Therefore, instead this results in an increase in exposure time, or there is the possibility of an increase in synchronization control error for the two stages. In the scanning stepper, since the synchronization control for the reticle and the wafer is important, then in reality, it cannot be considered to realize a shortening of exposure time by only increasing the speed and acceleration for the stage.
Incidentally, the flow of wafer processing for these types of apparatus is normally as follows.
At first, a rough alignment step is performed where prealignment (rough alignment) is carried out based on the beforementioned wafer external shape detection. Then, in the condition with the wafer stage moved to the loading position, the beforementioned transfer of the wafer (wafer loading step) to the wafer stage by the robot transport arm (loading arm) is performed. After this, a search alignment step is performed involving searching for the alignment marks on the wafer on the wafer stage, and correcting any position error of the wafer stage in the X, Y, xcex8 direction based on the results. After this, a fine alignment step is carried out involving precisely detecting the position of the alignment marks on the wafer to obtain the shot array on the wafer. After completion of this alignment, an exposure step is performed to transfer the pattern of the reticle onto the wafer. On completion of exposure, the wafer stage is again returned to the loading position and the beforementioned transport of the wafer using the unloading arm (unload arm) is performed (wafer unloading step: this wafer unloading step and the beforementioned wafer loading step constitute a wafer exchange step).
Consequently, the time required for processing one wafer is determined by; the wafer exchange time+the wafer rough search alignment time+the wafer fine alignment time+the exposure time. Therefore, also if the wafer exchange time apart from the exposure time is shortened, it is possible to realize a high throughput, as with increasing the stage speed.
However, with the above conventional example, it is necessary to go through procedures such as the above mentioned (1)xcx9c(10) procedures. Therefore there is the disadvantage that a long time is required for the exchange operation. Moreover, in this case after prealignment of the wafer, wafer transfer is carried out repeatedly. Consequently there is the disadvantage of a drop in prealignment accuracy. Moreover, since it is necessary to install an elevating drive mechanism such as the center-up pins on the wafer stage (XY stage), there is the disadvantage this additional weight, an increase in setting time for the stage, and a deterioration in controllability.
A first object of the present invention is to provide a substrate transport apparatus which enables prompt transfer of a substrate, and a substrate processing apparatus incorporating this. Here in the following description, in order to clarify the relationship between the various elements and the configurations disclosed in the figures, the reference numerals given in the figures are included for convenience. However, of course the various elements are not limited to the configurations disclosed in the figures.
In order to achieve the above objects, one configuration of the present invention is a substrate transport apparatus for transporting a substrate (W), and the apparatus comprises transport arms (45, 46, 145, 146) that support a peripheral portion of the substrate at at least two places on the peripheral portion and transports the substrate to a stage (7).
According to the substrate transport apparatus of the above aspect of the present invention, the transport arms support the peripheral portion of the substrate at at least two places on the peripheral portion, and transport the substrate to the stage. Therefore, before receiving the substrate, the transport arms can be moved to a transfer position where transfer of the substrate is possible, by horizontally moving the transport arms slightly from a standby position where relative vertical movement between the transport arms and the substrate is allowed. Furthermore, after transfer of the substrate, by horizontally moving the transport arms slightly from the substrate transfer position, the transport arms can be moved to the standby position for allowing relative vertical movement between the transport arms and the substrate. Consequently, the operation of substrate transfer becomes prompt.
Furthermore, in another preferred aspect, the transport arms comprise:
a first arm (45) having a first support portion (45e) for supporting a rear face of one side of the peripheral portions of the substrate in a transport direction (C-D) of the substrate, and a first facing portion (45f) provided on the first support portion so as to face a side face of the one side of the peripheral portion of the substrate;
a second arm (46) having a second support portion (46e) for supporting a rear face of the other side of the peripheral portions of the substrate in the transport direction of the substrate, and a second facing portion (46f) provided on the second support portion so as to face a side face of the other side of the peripheral portion of the substrate; and
a drive mechanism (43, 43a, 45a, 46a) for driving each of the first arm and the second arm so as to approach and separate from each other.
According to this aspect, with a simple construction and operation, a substrate can be quickly transferred, and a substrate can be reliably held and transported.
Furthermore, in another preferred aspect, the transport arm (145, 146) comprises a support portion (145c, 146c) which can be inserted into a cutout (71a) provided in a peripheral portion at a substrate support position (71) of the stage (7) on which the substrate is mounted so as to support a rear face of the substrate (W).
According to this aspect, prompt substrate transfer is possible with only operation of the transport arm.
Moreover, a substrate processing apparatus of the present invention comprises a table (71) for supporting a substrate, arms (145, 146) for transporting the substrate to the table (71), cutouts (71a) provided in the table periphery, and a support portion (145c, 146c) provided on the arm for inserting into the cutouts (71a) and supporting a rear face of the substrate (W).
According to such a substrate processing apparatus, prompt substrate transfer is possible with only operation of the transport arm.
Moreover, in another preferred aspect of the present invention, the support portions (145c, 146c) support a rear face of the substrate at at least two places on the peripheral portion.
According to this aspect, since the support portion supports the rear face of the substrate at at least two places on the peripheral portion, support of the substrate is stable.
Furthermore, in another preferred aspect, the transport arm (145, 146) comprises:
a first arm (145) having a first support portion (145c) serving as the support portion for supporting a rear face of one side of the peripheral portions of the substrate in a transport direction (C-D) of the substrate, and a first facing portion (145f) provided on the first support portion so as to face a side face of the one side of the peripheral portion of the substrate;
a second arm (146) having a second support portion (146c) serving as the support portion for supporting a rear face of the other side of the peripheral portions of the substrate in a transport direction of the substrate, and a second facing portion (146f) provided on the second support portion so as to face a side face of the other side of the peripheral portion of the substrate; and
a drive mechanism (143, 148, 149) for driving each of the first arm (145) and the second arm (146) so as to approach and separate from each other, and the first and second support portions (145c, 146c) respectively provided on the first and second arms, are able to be inserted in the cutouts (71a).
According to this aspect, with a simple construction and operation, a substrate can be reliably held and transported.
Moreover, in another preferred aspect, the substrate processing apparatus is an exposure apparatus for transferring a mask pattern to a photosensitive substrate.
Furthermore, a substrate transport apparatus of another aspect is a substrate transport apparatus for transferring a substrate to and from a substrate stage (7), and the apparatus comprises:
a first arm (45) having a first support portion (45e) for supporting from beneath one of a pair of opposite portions of the peripheral portions of the substrate which are approximately opposite in a transport direction (CD) of the substrate, and a first upright portion (45f) standing upright on the first support portion;
a second arm (46) having a second support portion (46e) for supporting from beneath the other of the pair of opposite portions, and a second upright portion (46f) standing upright on the second support portion for cooperating with the first upright portion to prevent movement of the substrate in a horizontal direction; and
an arm drive apparatus (43, 43a, 45a, 46a) for moving the first and second arms at the time of the substrate transport while maintaining a spacing of the first and second arms, and changing the spacing of the first and second arms at the time of transfer of the substrate.
According to a substrate transport apparatus of this aspect, prior to receiving the substrate, by merely bringing together the first and second arm slightly from the standby position where the first and second arms are spaced apart, the first and second arms can be moved to the transfer position. Moreover, after the substrate has been transferred, the first and second arms can be moved to the standby position by merely separating the first and second arms slightly from the transfer position. As a result, a substrate can be promptly transferred and the substrate can be reliably held and transported with a simple construction and operation.
Furthermore, in another preferred aspect, the first and second support portions (45e, 46e) are members having the same shape as the peripheral portion of the substrate.
According to this aspect, since the first and second support portions are each members having the same shape as the peripheral portion of the substrate, support of the substrate is more stable.
Furthermore, in another preferred aspect, at least one of the first and second arms further comprises a substrate sensor (45d, 46d) for detecting if the substrate is being supported on the arm.
According to this aspect, since at least one of the first and second arms further comprises a substrate sensor for detecting if the substrate is being supported on the arm, holding of the substrate is ensured.
Furthermore, in another preferred aspect, there is further provided a position sensor (47) for detected the spacing and position of the first and second arms.
According to this aspect, since there is further provided a position sensor for detected the spacing and position of the first and second arms, holding of the substrate is ensured.
Another object of the present invention is to provide a method of transferring a substrate which enables miniaturization of a stage for a substrate such as a wafer, of an exposure apparatus, and which can improve positioning accuracy at the time of mounting a substrate on the stage.
Furthermore, another object of the present invention is to provide a method of transferring a substrate, which can shorten the time for exchanging substrates on a substrate stage of an exposure apparatus, and which can improve positioning accuracy at the time of mounting a substrate on the stage.
Moreover, it is also an object of the present invention to provide an exposure apparatus which can employ such a substrate transfer method.
The method for transferring a substrate according to the present invention is a method which performs transfer of a substrate to and from a substrate stage (222) of an exposure apparatus for transferring a pattern of a mask (R1) onto a substrate (W) which is positioned or being moved by the substrate stage (222). This method comprises the steps of: providing a load arm (225, 228) for holding the substrate (W) and raising and lowering the substrate; detecting a position of the substrate by an external shape reference or by a predetermined alignment mark serving as a reference in a condition where the substrate is held by the load arm; moving the substrate stage based on the detection result to a position for receiving the substrate; lowering the load arm and mounting the substrate on the substrate stage; and then moving the load arm away from the substrate.
According to this method of transferring a substrate, when the substrate stage is moved to the loading position, that is to say, to beneath the load arm, then by lowering the load arm, the substrate is transferred from the load arm to the substrate stage. After this, by moving for example the substrate stage in the direction of the original position, the load arm can be withdrawn. As a result, there is no longer a need to provide a member in the substrate stage side for raising the substrate, and therefore, the construction of the substrate stage can be simplified, and the size reduced.
Furthermore, after measuring the position of the substrate (for example positional displacement amount from a predetermined reference position, and rotation error with respect to a reference direction) in the condition with the substrate being held by the load arm, the position of the substrate at the time of lowering the load arm onto the substrate stage hardly changes. Therefore, the positioning accuracy at the time of mounting the substrate on the substrate stage can be improved. Consequently, the search alignment can be practically omitted. Moreover, the position measurement (prealignment) of the substrate held by the load arm can be executed concurrently with a final alignment (fine alignment) and exposure for another substrate on the substrate stage. Therefore, the overall processing time can be further shortened, thus improving throughput.
In this case, when detecting the position of the substrate (W) held by the load arm (225, 228), the method preferably comprises the steps of detecting the positions of at least three places which include a cutout portion (N1, N2) formed on the peripheral portion of the substrate, computing a rotation angle of the substrate based on the detected positions, and rotating the load arm based on the computed results so as to correct the rotation angle of the substrate. In this case, because the rotational position error of the substrate is corrected before the substrate is loaded on the substrate stage, it is possible to omit an operation for correcting the rotational position error of the substrate on the substrate stage, the total processing time can thereby be shortened.
In the method of transferring a substrate according to the present invention, it is not necessary to provide the member for raising the substrate on the substrate stage side. Therefore, the substrate stage can be miniaturized, and the traversing speed and positioning accuracy (controllability) of the substrate stage can be improved. Moreover, since after measuring the position of the substrate on the load arm, the substrate is transferred as is onto the substrate stage, there is the advantage that the positioning accuracy at the time of mounting the substrate on the substrate stage can be improved.
Furthermore, in the case where positional displacement amount (xcex94WX, xcex94WY) of the center of the substrate from a predetermined detection center is obtained, this positional displacement amount (xcex94WX, xcex94WY) can be used for example as an offset amount at the time of performing final fine alignment of the substrate. Additionally, the loading position of the substrate stage may be corrected corresponding to this positional displacement amount (xcex94WX, xcex94WY).
Another aspect of the present invention is a method of transferring a substrate which performs transfer of a substrate to and from a substrate stage (222) of an exposure apparatus for transferring a pattern of a mask (R1) onto a substrate (W) which is positioned or being moved by the substrate stage (222).
This method uses a load arm (225, 228) for holding the substrate and lowering the substrate, and an unload arm (238) for holding the substrate and raising the substrate, and comprises:
a first step (S103, S104) for detecting a position of the substrate in a condition with the substrate being held by the load arm (225, 228);
a second step (S111, S113xcx9cS116) for moving the substrate stage (222) based on the detection results to a position for receiving the substrate, lowering the load arm and mounting the substrate on the substrate stage, and then moving the load arm away from the substrate stage;
a third step (S117, FIG. 27) for detecting the position of predetermined alignment marks (WM1xcx9cWM3) on the substrate, and, based on the detection results, obtaining a positional relationship between a plurality of regions to be exposed on the substrate and a pattern of the mask;
a fourth step (S117, FIG. 29) for successively transferring the pattern of the mask to the plurality of regions to be exposed on the substrate while performing alignment based on the obtained positional relationship; and
a fifth step (S111, S112) for moving the substrate stage to a position for unloading the substrate, raising the substrate with the unload arm and unloading from the exposure apparatus.
According to this aspect for the present invention, loading of the substrate is performed by a combination of an operation of moving the substrate stage to a position for performing loading of the substrate, and an operation for lowering the load arm (225, 228). Moreover, unloading of the substrate is performed by a combination of an operation for moving the substrate stage to a position for performing unloading of the substrate (preferably this is the same as the position for loading the substrate), and an operation for raising the unload arm (238). Therefore, exchange of the substrate can be performed at high speed. Furthermore, since the position of the substrate held on the load arm is detected in the first step, the accuracy of positioning the substrate on the substrate stage is improved. Moreover, since the positioning accuracy with respect to the substrate stage is improved, then, in the third step, substantially direct alignment rather than search alignment can be performed so that throughput is improved.
According to the above mentioned method of transferring a substrate, transfer of the substrate can be performed by a combination of an operation for moving the substrate stage in the horizontal direction, and vertically moving the load arm and the unload arm. Therefore, the time for exchanging substrates on the substrate stage can be shortened. Furthermore, since after measuring the position of the substrate on the load arm, the substrate is transferred to the substrate stage, the positioning accuracy at the time of mounting the substrate on the substrate stage can be improved. Therefore in the third step, search alignment can be practically omitted, and the throughput of the exposure process can be improved.
Another aspect of the present invention is an exposure apparatus comprising a substrate stage (222) for performing positioning or moving of a substrate (W1), an exposure section (210, 213, 217) for transferring a pattern of a mask (R1) to a substrate on the substrate stage, a load arm (225, 228) for holding the substrate and raising and lowering the substrate, an image processing system (226, 245) for detecting a position of the substrate held on the load arm, and a control system (215, 205) for controlling operation of the substrate stage and the load arm based on detection results from the image processing system. The control system moves the substrate to a position for receiving the substrate based on the position of the substrate detected by the image processing system, and lowers the load arm so as to mount the substrate on the substrate stage. This exposure apparatus employs the first method of transferring a substrate of the present invention.
In this case, preferably the image processing system comprises a moveable illumination apparatus (245) which can be brought into and taken out from beneath the load arm (225, 228) for illuminating the substrate from the bottom face side, and an imaging apparatus (226) for imaging an image of an external shape of the substrate illuminated by the moveable illumination apparatus. By imaging the image of the substrate in this way with a transmission light, the position of the substrate can be measured to a high accuracy without influence of for example non uniformity in the reflectivity of the surface of the edge portion of the substrate. Furthermore, at the time of lowering the load arm onto the substrate stage, the moveable illumination apparatus (245) can be withdrawn so that the moveable illumination apparatus (245) does not interfere.
In the case where the substrate is a large size (for example a wafer of 12 inches diameter (approximately 300 mm)), the moveable illumination apparatus (245) may be moved to follow detection points (226L, 226N1, 226R and 226U, 226N2, 226R) on the substrate at the time of position detection of the substrate. In this way, the moveable projection apparatus can be made small and hence withdrawal is facilitated. Moreover, the zero degree notch and the 90xc2x0 degree notch of for example a 12 inch diameter wafer can be successively detected by rotating the same moveable illumination apparatus. Furthermore, the moveable illumination apparatus may comprise a surface light source (fluorescent lamp, fluorescent plate etc.) having a wide illumination field so that both wafer notch detection and detection of a separate wafer orientation flat portion can be performed.
Furthermore, the load arm (225, 228) may incorporate a holding member (228) for holding the substrate by holding from above, and grooves (237A, 237B) for accommodating tip end portions (250A, 250B) of the holding member (228) may be formed in the substrate mounting surface (221) of the substrate stage (222). In this case, when the load arm is lowered onto the substrate stage, the tip end portions (250A, 250B) of the holding members are accommodated in the grooves (237A, 237B) on the substrate stage. Therefore, the substrate can be easily transferred to the substrate stage. After this, by moving the substrate stage in a parallel direction to the grooves (237A, 237B), the load arm can be withdrawn from the substrate stage.
The width of the grooves (237A, 237B) may be made wide so that, after mounting the substrate on the substrate stage, the load arm can be spread and raised so as to be withdrawn from the substrate stage.
There may be further provided an unload arm which can be raised and lowered for unloading the substrate on the substrate stage (222), and the load arm may also incorporate a holding member (238) for holding the substrate by holding from above, and tip end portions (249A, 249B) of the holding member may also be freely accommodated in the grooves (237A, 237B) on the substrate stage. In this case, at the time of unloading the substrate, the substrate can be easily unloaded by moving the substrate stage so that the tip end portions of the unload arm are accommodated in the grooves, and then raising the unload arm.
Furthermore, preferably the load arm (225, 228) comprises a function for rotating and raising the substrate, and a transport arm (243) for transporting the substrate to be exposed from the substrate transport line to the load arm (225, 228) is separately provided. In this case, preferably the unload arm (238) is given a function enabling movement to the substrate transport line after receiving the substrate, and a base member (242) supporting the transport arm (243) and the unload arm (238), and a base member (248) supporting the load arm (225, 228) and the image processing system (226, 245) are made independent of each other. In the case where a projection optical system (217) is provided, it is preferable that the projection optical system (217) is also secured to the latter base member (248). In this case, the influence of vibration when transporting the substrate between the transport line and the substrate line is not exerted at the time of performing position detection of the substrate on the load arm, and at the time of passing the substrate onto the substrate stage. Therefore the accuracy of positioning the substrate with respect to the substrate stage is improved.
That is to say, with the first exposure apparatus of the present invention, the first substrate transfer method can be used. Moreover, when the unload arm is provided, the second substrate transfer method can be used.
Another object of the present invention is to provide a substrate transport method and substrate transport apparatus which can unload a substrate from a substrate holding member in a shorter time.
Furthermore, another object of the present invention is to provide a substrate transport method and substrate transport apparatus which can load a substrate onto a substrate holding member in a shorter time and at high accuracy.
Moreover, another object of the present invention is to provide a substrate transport method and substrate transport apparatus which can shorten the time for exchanging a substrate on the substrate holding member.
Furthermore, another object of the present invention is to provide an exposure apparatus which can enable an improvement in throughput by shortening the substrate exchange time.
Moreover, another object of the present invention is to provide a device manufacturing method which can enable an improvement in device productivity.
Another aspect of the present invention is a substrate transport method for unloading a substrate (W) from a substrate holding member (318) which is moveable in a two dimensional plane. This method comprises: a first step for standing by an unload arm (352) at a substrate transfer position; a second step for moving the substrate holding member holding the substrate to the substrate transfer position, and passing the substrate from the substrate holding member to the unload arm; and a third step for relatively moving the unload arm and the substrate holding member to withdraw the unload arm holding the substrate from the substrate holding member.
In this method, at first, the unload arm is stood by at the substrate transfer position. Then, the substrate holding member which is holding a substrate is moved to the substrate transfer position, and the substrate is passed from the substrate holding member to the unload arm. After this, the unload arm and the substrate holding member are moved relatively so that the unload arm which is holding the substrate is withdrawn from the substrate holding member. Therefore, concurrent with standing by the unload arm at the substrate transfer position, various processing can be performed on the substrate which is held on the substrate holding member. Furthermore, the transfer of the substrate from the substrate holding member to the unload arm is performed, not with the unload arm, but by moving the substrate holding member which moves at a higher speed, to the substrate transfer position. Moreover the withdrawal of the unload arm which is holding the substrate after completion of the transfer, from the substrate holding member is performed by relative movement between the unload arm and the substrate holding member. Therefore, compared to conventional unloading of the substrate by a common operation involving the unloading arm and the center-up, high speed unloading (unloading) of the substrate from the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, when in the second step the substrate (W) is passed from the substrate holding member (318) to the unload arm (352), at least one of the substrate holding member and the unload arm may be moved in a direction orthogonal to the two dimensional plane. In this case, due to the relative movement between the substrate holding member and the unload arm in the direction orthogonal to the two dimensional plane, the substrate holding member and the unload arm which is holding the substrate can be separated. Therefore, the relative movement in the third step between the unload arm and the substrate holding member can be started earlier.
Another aspect of the present invention is a substrate transport method for loading a substrate (Wxe2x80x2) onto a substrate holding member (318) which is moveable in a two dimensional plane. This method comprises: a first step for standing by at a substrate transfer position a load arm (336) which is holding a substrate (Wxe2x80x2); a second step for moving the substrate holding member to the substrate transfer position, and passing the substrate from the load arm to the substrate holding member and; and a third step for relatively moving the substrate holding member and the load arm to separate the substrate from the load arm.
In this method, at first, the load arm holding a substrate is stood by at the substrate transfer position. Then, the substrate holding member is moved to the substrate transfer position, and the substrate is passed from the load arm to the substrate holding member. After this, the substrate holding member and the load arm are moved relatively to separate the substrate from the load arm. That is to say, since the substrate is passed from the load arm to the substrate holding member, then rather than the load arm, the substrate holding member which moves faster, is moved to the substrate transfer position. Moreover, the separation after completion of the transfer, of the substrate (that is, the substrate holding member which is holding the substrate) from the load arm, is also performed by relative movement between the substrate holding member and the load arm. Therefore, compared to conventional loading of the substrate by a common operation involving the loading arm and the center-up, high speed loading of the substrate onto the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, when in the second step the substrate (Wxe2x80x2) is passed from the load arm (336) to the substrate holding member (318), at least one of the substrate holding member and the load arm may be moved in a direction orthogonal to the two dimensional plane. In this case, due to the relative movement between the substrate holding member and the load arm in the direction orthogonal to the two dimensional plane, then simultaneously with the passing of the substrate from the load arm to the substrate holding member, the substrate can be separated from the load arm. Therefore, substrate loading can be completed even more quickly. That is to say, the substrate can be separated from the load arm before commencing the relative movement of the third step.
Another aspect of the present invention is a substrate transport method for unloading a substrate (W) from a substrate holding member (318) which is moveable in a two dimensional plane, and loading another substrate (Wxe2x80x2) onto the substrate holding member. This method comprises: a first step standing by at a substrate transfer position an unload arm (352) and a load arm (336) which is holding another substrate (Wxe2x80x2); a second step for moving the substrate holding member which is holding the substrate to the substrate transfer position, and passing the substrate from the substrate holding member to the unload arm; a third step for withdrawing the unload arm which is holding the substrate from the substrate holding member; and a fourth step for after withdrawing the unload arm, passing the other substrate from the load arm to the substrate holding member.
In this method, at first, the unload arm and the load arm holding another substrate (for convenience referred to as xe2x80x9csecond substratexe2x80x9d) are stood by at the substrate transfer position, and the substrate holding member which is holding a substrate (for convenience referred to as xe2x80x9cfirst substratexe2x80x9d) is moved to the substrate transfer position, and the first substrate is passed from the substrate holding member to the unload arm. Then, the unload arm which is holding the first substrate is withdrawn from the substrate holding member, and after withdrawal of the unload arm, the second substrate is passed from the load arm to the substrate holding member. Therefore, concurrent with the standing by at the substrate transfer position of the unload arm and the load arm which is holding the second substrate, various processing can be performed on the first substrate which is being held on the substrate holding member. Moreover, the transfer of the substrate from the substrate holding member to the unload arm is performed, not with the unload arm, but by moving the substrate holding member which moves at a higher speed, to the substrate transfer position. Then on completion of the transfer, the unload arm which is holding the first substrate is withdrawn from the substrate holding member, and after withdrawal of the unload arm, the second substrate is passed from the load arm to the substrate holding member. Therefore, compared to the conventional case where the exchange of the substrate on the substrate holding member is performed by a common operation of the unloading arm and the center-up, and a common operation of the loading arm and the center-up, high speed exchange of the substrate on the substrate holding member, that is, unloading and loading becomes possible, enabling a shortening of the substrate exchange time.
In this case, when in the second step the substrate (W) is passed from the substrate holding member (318) to the unload arm (352), at least one of the substrate holding member and the unload arm may be moved in a direction orthogonal to the two dimensional plane, and when in the fourth step, after the unload arm withdrawal, another substrate (Wxe2x80x2) is passed from the load arm (336) to the substrate holding member, at least one of the substrate holding member and the load arm may be moved in a direction orthogonal to the two dimensional plane. In this case, in the second step, due to the relative movement between the substrate holding member and the unload arm in the direction orthogonal to the two dimensional plane, the substrate holding member and the unload arm which is holding the first substrate can be separated. Furthermore, in the fourth step, due to the relative movement between the substrate holding member and the load arm in the direction orthogonal to the perpendicular plane, the second substrate can be passed from the load arm to the substrate holding member, and simultaneously the second substrate can be separated from the load arm.
Another aspect of the present invention is a substrate transport method for unloading a substrate from a stage (WST) which is moveable in a two dimensional plane. This method prepares beforehand a substrate holding member (318) provided on the stage, and formed with concavities or cutouts (330a, 330b) extending in a predetermined direction such that at least a part of an unload arm (352) is insertable therein in a condition with the substrate held on a substrate contact face side, and the method comprises: a first step for standing by the unload arm at a substrate transfer position; a second step for moving the stage towards the substrate transfer position in order to insert at least a part (350a, 350b) of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate; and a third step for after inserting at least a part of the unload arm into the concavities or cutouts, relatively moving the unload arm and the substrate holding member in a direction orthogonal to the two dimensional plane to separate the substrate from the substrate holding member.
According to this method, at first, the unload arm is stood by at the substrate transfer position. Then, the substrate stage is moved towards the substrate transfer position in order to insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate. Subsequently, after inserting at least a part of the unload arm into the concavities or cutouts, the unload arm and the substrate holding member are moved relatively in a direction orthogonal to the two dimensional plane, to separate the substrate from the substrate holding member. Therefore, concurrent with standing by the unload arm at the substrate transfer position, various processing can be performed on the substrate which is held on the substrate holding member. Furthermore, the transfer of the substrate from the substrate holding member to the unload arm is performed, not with the unload arm, but by moving the stage (that is, substrate holding member) which moves at a higher speed, to the substrate transfer position. Then, after inserting at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate, separating the substrate from the substrate holding member by relatively moving the unload arm and the substrate holding member in the direction orthogonal to the two dimensional plane. Consequently, compared to conventional unloading of the substrate by a common operation involving the unloading arm and the center-up, high speed unloading of the substrate from the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, the operation in the second step of inserting at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding a substrate, can of course be performed by moving the substrate stage towards the substrate transfer position with the loading arm stopped at the substrate transfer position. However, when in the second step at least a part (350a, 350b) of the unload arm (352) is inserted into the concavities or cutouts (330a, 330b), the unload arm may be simultaneously driven in the predetermined direction (the extension direction of the concavities or cutouts). In this case, the unload arm can be inserted into the concavities or cutouts in a shorter time, thus enabling even higher speed unloading of the substrate from the substrate holding member.
Another aspect of the present invention is a substrate transport method for loading a substrate (Wxe2x80x2) onto a stage (WST) which is moveable in a two dimensional plane. This method prepares beforehand a substrate holding member (318) provided on the stage, and formed with concavities or cutouts (330a, 330b) extending in a predetermined direction such that at least a part (350a, 350b) of a load arm (336) is insertable therein, and the method comprises: a first step for standing by the load arm which is holding a substrate at a substrate transfer position: a second step for moving the stage towards the substrate transfer position; a third step for inserting at least a part of the load arm into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane; and a fourth step for after passing the substrate from the load arm to the substrate holding member, relatively moving the load arm and the stage to separate the substrate from the load arm.
In this method, at first the load arm holding the substrate is stood by at the substrate transfer position. Then, the stage (that is, the substrate holding member) is moved towards the substrate transfer position, and at least a part of the load arm is inserted into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane. After this, the substrate is passed from the load arm to the substrate holding member, and the load arm and the stage are moved relatively so that the substrate is separated from the load arm. That is to say, in order to pass the substrate from the load arm to the substrate holding member, then, rather than the load arm, the stage which moves faster, is moved towards the substrate transfer position, and at least a part of the load arm is inserted into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane, and the substrate is passed to the substrate holding member. After the substrate has been passed from the load arm to the substrate holding member, the load arm and the stage are moved relatively so that the substrate is separated from the load arm. Therefore, compared to the conventional loading of the substrate by a common operation involving the loading arm and the center-up, high speed loading of the substrate onto the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, in the third step, it is of course possible to insert at least a part of the load arm into the concavities or cutouts of the holding member after completion of moving the stage to the substrate transfer position. However, in the third step, the insertion of at least a part (350a, 350b) of the load arm (336) into the concavities or cutouts (330a, 330b) of the substrate holding member (318) may be carried out during movement of the stage (WST). In this case, at least a part of the load arm can be inserted into the concavities or cutouts of the substrate holding member before completion of movement of the stage to the substrate transfer position. Therefore, the substrate can be more quickly passed from the load arm to the substrate holding member. However, in order to accurately pass the substrate to a predetermined position on the substrate holding member, it is necessary to have a aspect where the substrate holding member can move on the stage, or to move the load arm simultaneously in the opposite direction to the moving direction of the stage.
For this reason, when at least a part (350a, 350b) of the load arm (336) is inserted into the concavities or cutouts (330a, 330b) in the third step, it is desirable to move the load arm in a direction orthogonal to the two dimensional plane, and to simultaneously drive this in the predetermined direction.
Another aspect of the present invention is a substrate transport apparatus for unloading a substrate (W) from a stage (WST) which is moveable in a two dimensional plane. This apparatus comprises: an unload arm (352); an arm drive mechanism (356) for driving the unload arm; a substrate holding member (318) provided on the stage and formed with concavities or cutouts (330a, 330b) extending in a predetermined direction such that at least a part (350a, 350b) of the load arm is insertable therein, in a condition with the substrate held on a substrate contact face side; a stage drive unit (305) for driving the stage in the two dimensional plane; a relative drive mechanism (358) for relatively driving the unload arm and the substrate holding member in a direction orthogonal to the two dimensional plane; and a control unit (319, 320, 321). This control unit (319, 320, 321) has a first function for moving the unload arm via the arm drive mechanism to a substrate transfer position, a second function for moving the substrate stage via the stage drive mechanism towards the substrate transfer position in order to insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate, and a third function for after inserting the unload arm into the concavities or cutouts, separating the substrate from the substrate holding member via the relative drive mechanism.
In this apparatus, at first by means of the control unit, the unload arm is moved to the substrate transfer position via the arm drive mechanism. Then, the stage is moved via the stage drive unit towards the substrate transfer position in order to insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding a substrate. Then, after the unload arm has been inserted into the concavities or cutouts, the substrate is separated from the substrate holding member via the relative drive mechanism. Therefore, concurrent with standing by the unload arm at the substrate transfer position, various processing can be performed on the substrate which is held on the substrate holding member. Furthermore, the transfer of the substrate from the substrate holding member to the unload arm is performed, not with the unload arm, but by moving the stage (that is, substrate holding member) which moves at a higher speed, to the substrate transfer position. Then, after inserting at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate, the substrate is separated from the substrate holding member by relatively moving the unload arm and the substrate holding member in the direction orthogonal to the two dimensional plane. Consequently, compared to conventional unloading of the substrate by a common operation involving the unloading arm and the center-up, high speed unloading of the substrate from the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, the control unit (319, 320, 321) may further have a fourth function, for relatively moving the unload arm and the stage (WST) to withdraw the unload arm from the substrate holding member, after the substrate (W) has been transferred from the substrate holding member (318) to the unload arm (352). In this case, the withdrawal of the unload arm from the substrate holding member after the substrate has been transferred from the substrate holding member to the unload arm is possible by moving at least one of the unload arm and the stage. Therefore, as a result, the substrate can be quickly withdrawn from the unload arm, enabling the processing of the substrate after withdrawal to be started promptly.
In the above substrate transport apparatus, the control unit may move only the stage (WST) towards the substrate transfer position with the unload arm in the standby condition at the substrate transfer position, to thereby insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding a substrate. However, the control unit (319, 320, 321) may control the arm drive mechanism (356) so that at the time of inserting at least a part (350a, 350b) of the unload arm (352) into the concavities or cutouts (330a, 330b), the unload arm is simultaneously moved in the predetermined direction. In this case, the unload arm can be more quickly inserted into the concavities or cutouts.
Moreover, in the substrate transport apparatus, the control unit (319, 320, 321) may, after inserting at least a part (350a, 350b) of the unload arm (352) into the concavities or cutouts (330a, 330b), control at least one of the arm drive mechanism (356) and the stage drive unit (315) so as to relatively move the unload arm and the stage (WST) in the predetermined direction. In this case, the insertion of the unload arm into the concavities or cutouts can be completed sooner, and the subsequent relative movement of the unload arm and the substrate holding member in the direction orthogonal to the two dimensional plane can be started that much earlier.
Another aspect of the present invention is a substrate transport apparatus for loading a substrate (Wxe2x80x2) onto a stage (WST) which is moveable in a two dimensional plane, and this apparatus comprises: a load arm (336) for holding a substrate at a substrate transfer position; a substrate holding member (318) provided on the stage and formed with concavities or cutouts (330a, 330b) extending in a predetermined direction such that at least a part (350a, 350b) of the load arm is insertable therein; a stage drive unit (315) for driving the stage in the two dimensional plane; a relative drive mechanism (338) for relatively driving the load arm and the substrate holding member in a direction orthogonal to the two dimensional plane; and a control unit (319, 320, 321). This control unit (319, 320, 321) has a first function for moving the stage via the stage drive mechanism towards the substrate transfer position, a second function for making the load arm approach the substrate holding member by means of the relative drive mechanism to thereby insert at least a part of the load arm into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane, and a third function for after the substrate has been passed from the load arm to the substrate holding member, relatively moving the load arm and the stage to separate the substrate from the load arm.
In this apparatus, the load arm which is holding the substrate is stood by at the substrate transfer position. Then, the control unit, via the stage drive unit, moves the stage towards the substrate transfer position. After this, the control unit, via the relative drive mechanism, makes the load arm approach the substrate holding member to thereby insert at least a part of the load arm into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane. As a result, the substrate is passed from the load arm to the substrate holding member. After this, the load arm and the stage are relatively moved by the control unit so that the substrate is separated from the load arm. That is to say, in order to pass the substrate from the load arm to the substrate holding member, rather than the load arm, the stage which moves faster, is moved towards the substrate transfer position, and at least a part of the load arm is inserted into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane, and the substrate is passed to the substrate holding member. After the substrate has been passed from the load arm to the substrate holding member, the load arm and the stage are moved relatively so that the substrate is separated from the load arm. Therefore, compared to the conventional loading of the substrate by a common operation involving the loading arm and the center-up, high speed loading of the substrate onto the substrate holding member becomes possible, enabling an improvement in throughput.
In this case, of course, the control unit may insert at least a part of the load arm into the concavities or cutouts of the substrate holding member after completion of the movement of the stage to the substrate transfer position. However, the control unit (319, 320, 321) may insert at least a part of the load arm (336) into the concavities or cutouts (330a, 330b) of the substrate holding member (318) during movement of the stage (WST). In this case, the substrate can be passed from the load arm to the substrate holding member in a shorter time.
Moreover, in the case where the substrate transport apparatus is further provided with an arm drive mechanism for driving the load arm (336), then the control unit (319, 320, 321), when at least a part (350a, 350b) of the load arm (336) is inserted into the concavities or cutouts from a direction orthogonal to the two dimensional plane, may control the arm drive mechanism to drive the load arm in the predetermined direction in addition to driving in the direction orthogonal to the two dimensional plane. In this case, transfer of the substrate to a predetermined position on the substrate holding member can be completed before completion of moving the stage to the substrate transfer position.
Alternatively, a drive unit for driving the load arm (336) may be further provided in the substrate transport apparatus, and after inserting at least a part (350a, 350b) of the load arm (336) into the concavities or cutouts (330a, 330b), the control unit (319, 320, 321) may control at least one of the arm drive mechanism and the stage drive unit (315) to relatively move the load arm and the stage (WST) in the predetermined direction.
Another aspect of the present invention is a substrate transport apparatus for unloading a substrate (W) from a stage (WST) which is moveable in a two dimensional plane, and for loading another substrate (Wxe2x80x2) onto the stage. This apparatus comprises: an unload arm (352); a load arm (336) for holding the substrate at a substrate transfer position; an arm drive mechanism (356) for driving the unload arm; a substrate holding member (318) provided on the stage and formed with concavities or cutouts (330a, 330b) extending in a first direction such that at least a part (350a, 350b) of the unload arm is insertable therein in a condition with the substrate held on a substrate contact face side, and at least a part of the load arm is insertable therein; a relative drive mechanism (338, 358) for relatively driving at least one of the unload arm and the load arm, and the substrate holding member in a direction orthogonal to the two dimensional plane; a stage drive unit (315) for driving the stage in the two dimensional plane; and a control unit (319, 320, 321). This control unit (319, 320, 321) has a first function for moving the unload arm via the arm drive mechanism to the substrate transfer position, a second function for moving the substrate stage via the stage drive mechanism towards the substrate transfer position in order to insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding the substrate, a third function for after inserting the unload arm into the concavities or cutouts, separating the substrate from the substrate holding member via the relative drive mechanism, a fourth function for withdrawing the unload arm via the arm drive mechanism from the substrate transfer position, a fifth function for after withdrawing the unload arm making the load arm approach the substrate holding member by means of the relative drive mechanism to thereby insert at least a part of the load arm into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane, and a sixth function for, after the substrate has been passed from the load arm to the substrate holding member, relatively moving the load arm and the stage to separate the substrate from the load arm.
In this apparatus, the control unit moves the unload arm via the arm drive mechanism to the substrate transfer position, and moves the substrate stage via the stage drive mechanism towards the substrate transfer position in order to insert at least a part of the unload arm into the concavities or cutouts of the substrate holding member which is holding a substrate. Then, after insertion of the unload arm into the concavities or cutouts, the control unit separates the substrate from the substrate holding member via the relative drive mechanism. Next, the control unit withdraws the unload arm from the substrate transfer position via the arm drive mechanism. After this unload arm withdrawal, the control unit, via the relative drive mechanism, makes the load arm approach the substrate holding member to thereby insert at least a part of the load arm into the concavities or cutouts of the substrate holding member from a direction orthogonal to the two dimensional plane. Then, after passing the substrate from the load arm to the substrate holding member, relatively drives the load arm and the stage so that the substrate is separated from the load arm. Therefore, compared to the conventional case where the exchange of the substrate on the substrate holding member is performed by a common operation of the unloading arm and the center-up, and a common operation of the loading arm and the center up, high speed exchange of the substrate on the substrate holding member, that is unloading and loading becomes possible, enabling a shortening of the substrate transfer time, and an improvement in accuracy due to the small number of transfers after alignment.
In the above described substrate transport apparatus, the load arm (336) may be arranged at the substrate transfer position, and may be able to hold the substrate and rotate within a plane of the substrate. In this case, the apparatus may further comprise: a measuring device (340a, 340b, 340c) for measuring an external shape of a substrate (Wxe2x80x2) held in the load arm; a computing unit (321) for computing a positional displacement of the substrate within a plane parallel to the two dimensional plane based on measurement results of the measurement device; and a second control unit (320, 321) for controlling a rotation amount of the load arm to correct positional displacement of the substrate in a rotation direction computed by the computing unit.
In this case, before the stage is moved to the substrate transfer position, the external shape of the substrate held in the load arm can be measured by the measurement device, and based on the measurement result of the measurement device, the positional displacement of the substrate within a plane parallel to the two dimensional plane can be computed by the computing unit. The rotation amount of the load arm can then be controlled by the second control unit to correct the positional displacement of the substrate in the rotation direction computed by the computing unit. That is to say, prior to moving the stage to the substrate transfer position for unloading the substrate from the substrate holding member, rotation correction for the next substrate can be completed. Therefore, rotation correction of the substrate (prealignment) without any drop in throughput is possible.
In the abovementioned substrate transport apparatus, the unload arm (352) and load arm (336) may have prongs (350a, 350b) of a shape which is insertable into the concavities or cutouts (330a, 330b), and a space may be provided above the prongs such that the substrate can be moved in and out thereof in a second direction different from the first direction. In this case, the insertion and removal of the prongs of the unload arm and the load arm with respect to the concavities or cutouts of the substrate holding member may be performed by relatively moving the stage and the unload arm and the load arm in the first direction, and the loading or unloading of the substrate with respect to the substrate unload arm and load arm may be performed by moving the substrate in and out in the second direction.
In the abovementioned various aspects, the concavities or cutouts may include a first concavity formed in a position different from the substrate contact face and extending in a predetermined direction, and a second concavity communicated with the first concavity and formed in the substrate contact face, and based on the first concavity and the second concavity, a path with a L shape as seen from the side for guiding the unload arm may be formed. In such a case, a part of the substrate contact face protrudes at the part of the cutout extending in the predetermined direction on the opposite side thereof to the stage. Therefore, also in the case where a substrate with for example poor flatness is mounted on the substrate holding member, the substrate contacts the substrate holding face over substantially the whole face and is made flat. Therefore, the substrate is held on the substrate holding member with good flatness. Furthermore, when the unload arm is inserted into the cutouts of the substrate holding member with the substrate being held, the occurrence of any undesirable situation such as the insertion disturbing the substrate can be reliably avoided. Moreover, the contact area of the substrate contact face with respect to the substrate can be made even larger.
Another aspect of the present invention is an exposure apparatus for transferring a predetermined pattern onto a substrate on a stage (WST), and this exposure apparatus is provided with the above mentioned substrate transport apparatus as an apparatus for exchanging substrates on the stage.
In this way, by means of the substrate transport apparatus of the abovementioned various aspects, the speed of at least one of the loading of the substrate to the substrate holding member, and the unloading of the substrate from the substrate holding member can be increased, and therefore, an improvement in throughput is possible.
Another aspect of the present invention is an exposure apparatus for transferring a predetermined pattern onto a substrate on a stage (WST), and this exposure apparatus comprises the substrate transport apparatus as an apparatus for exchanging substrates on the stage, and a mark detection system (ALG) for detecting position detection marks on the substrate. The second control unit (320, 321) corrects positional displacement of the substrate in the two dimensional plane detected by the computing unit (321), using any of the corrections for; the positioning of the load arm (336), the positioning of the stage (WST), and the detection result for the position detection mark by the mark detection system (ALG).
In this exposure apparatus, since the substrate transport apparatus is provided as the apparatus for exchanging substrates on the stage, an improvement in throughput is possible due to the shortening of the time for exchanging substrates on the substrate holding member. Furthermore, in this case the mark detection system is further provided for detecting position detection marks on the substrate, and the second control unit corrects positional displacement of the substrate in the two dimensional plane detected by the computing unit, using any of the corrections for; the positioning of the load arm, the positioning of the stage, and the detection result for the position detection mark by the mark detection system. Therefore, prior to moving the stage to the substrate transfer position in order to unload the substrate from the substrate holding member, the rotation correction for the next substrate can be completed. Therefore, in addition to rotation correction of the substrate (prealignment) being possible without any drop in throughput, positional adjustment of both at the time of substrate transfer becomes unnecessary. Therefore, transfer time is shortened and the number of transfers reduced, thus enabling an improvement in substrate prealignment accuracy.
In this case, it is preferable to perform concurrently, the external shape measurement of the substrate by the measuring device, the computation of the positional displacement of the substrate by the computing unit, and the rotation correction of the substrate by the second control unit, at the same time as the operations on the substrate until completion of transfer of the mask pattern to the substrate.
Furthermore, the device manufacturing method of the present invention comprises an exposure step for performing exposure using the above described exposure apparatus.